Method of treating multiple myeloma using combination therapies based on anti-cs1 antibodies

ABSTRACT

Compositions and methods for treating MM are provided herein.

1. CROSS REFERENCE TO RELATED APPLICATIONS

This application claims benefit under 35 U.S.C. §119(e) to applicationSerial Nos. 60/836,185, filed Aug. 7, 2006 and 60/944,262, filed Jun.15, 2007, the contents of which are incorporated herein by reference.

2. BACKGROUND

Multiple myeloma (“MM”) represents a malignant proliferation of plasmacells derived from a single clone. The terms multiple myeloma andmyeloma are used interchangeably to refer to the same condition. Themyeloma tumor, its products, and the host response to it result in anumber of organ dysfunctions and symptoms of bone pain or fracture,renal failure, susceptibility to infection, anemia, hypocalcemia, andoccasionally clotting abnormalities, neurologic symptoms and vascularmanifestations of hyperviscosity. See D. Longo, in Harrison's Principlesof Internal Medicine 14th Edition, p. 713 (McGraw-Hill, New York, 1998).No effective long-term treatment currently exists for MM. It is amalignant disease of plasma cells, manifested as hyperproteinemia,anemia, renal dysfunction, bone lesions, and immunodeficiency. MM isdifficult to diagnose early because there may be no symptoms in theearly stage. The disease has a progressive course with a median durationof survival of six months when no treatment is given. Systemicchemotherapy is the main treatment, and the current median of survivalwith chemotherapy is about three years, however fewer than 5% livelonger than 10 years (See Anderson, K. et al., Annual Meeting Report1999. Recent Advances in the Biology and Treatment of Multiple Myeloma(1999)).

While multiple myeloma is considered to be a drug-sensitive disease,almost all patients with MM who initially respond to chemotherapyeventually relapse (See Anderson, K. et al., Annual Meeting Report 1999.Recent Advances in the Biology and Treatment of Multiple Myeloma(1999)). Since the introduction of melphalan and prednisone therapy forMM, numerous multi-drug chemotherapies including Vinca alkaloid,anthracycline, and nitrosourea-based treatment have been tested (SeeCase, D C et al., (1977) Am. J. Med 63:897 903), but there has beenlittle improvement in outcome over the past three decades (See Case, D Cet al., (1977) Am. J. Med 63:897 903; Otsuki, T. et al, (2000) CancerRes. 60:1). New methods of treatment, such as combination therapiesutilizing monoclonal antibodies and therapeutic agents, are needed.

3. SUMMARY

Described herein are compositions and methods useful for exploiting theanti-tumor properties of anti-CS1 antibodies. Anti-CS1 antibodies thatcan be used in the methods and compositions are described in U.S. PatentPublication Nos. 2005/0025763 and 2006/0024296, the contents of whichare incorporated herein by reference. The anti-CS1 antibodies target CS1(CD2-subsetl), which is also known as SLAMF7, CRACC, 19A, APEX-1, andFOAP12 (Genbank Accession Number NM 021181.3). CS1, is a glycoproteinthat is highly expressed in bone marrow samples from patients diagnosedwith MM. In both in vitro and in vivo studies, anti-CS1 antibodiesexhibit significant anti-myeloma activity (see, e.g., U.S. PatentPublication Nos. 2005/0025763 and 2006/0024296, the contents of whichare incorporated herein by reference). By way of example, but notlimitation, the anti-CS1 antibody, HuLuc63 effectively mediates lysis ofmyeloma cells via antibody dependent cellular cytotoxicity (ADCC) (see,e.g., U.S. Patent Publication No. 2005/0025763, the content of which isincorporated herein by reference). In a myeloma mouse tumor model,treatment with HuLuc63 significantly reduced tumor mass by more than 50%(see, e.g., U.S. Patent Publication No. 2005/0025763, the content ofwhich is incorporated herein by reference).

The present disclosure relates to compositions and methods for treatingpatients diagnosed with Monoclonal Gammopathy of UndeterminedSignificance (MGUS), smoldering myeloma, asymptomatic MM, andsymptomatic MM, ranging from newly diagnosed to late stagerelapsed/refractory. In particular, the methods relate to theadministration of a pharmaceutical composition comprising an anti-CS1antibody, such as HuLuc63, in combination with one or more therapeuticagents. The anti-CS1 antibody is typically administered in a firstpharmaceutical composition as an intravenous infusion at doses rangingfrom 0.5 to 20 mg/kg, from once a week to once a month.

A second pharmaceutical composition comprising one or more therapeuticagents, such as bortezomib and lenalidomide, can be administeredconcurrently, prior to, or following administration of an anti-CS1antibody. Depending on the agent, the composition can be administeredorally, intravenously or subcutaneously. Therapeutic agents can be usedat high dose rates, standard dose rates and at reduced dose rates.

In some embodiments, administration of the pharmaceutical compositionsdescribed herein increases the sensitivity of multiple myeloma cells toa therapeutic agent. By way of example, but not limitation, inclusion ofan anti-CS1 antibody can enhance the activity of the therapeutic agent,such that lower doses can be used in the compositions and methodsdescribed herein.

In some embodiments, administration of the pharmaceutical compositionsdescribed herein elicits at least one of the beneficial responses asdefined by the European Group for Blood and Marrow transplantation(EBMT). For example, administration of the pharmaceutical compositionsdescribed herein can result in a complete response, partial response,minimal response, no change, or plateau.

4. BRIEF DESCRIPTION OF THE FIGURES

FIGS. 1A-1C depict autologous ADCC-mediated lysis of MM cells treatedwith HuLuc63;

FIGS. 2A-2B depict HuLuc63 induced ADCC against Hsp90 and bortezomibresistant patient tumor cells;

FIGS. 3A-3C depict enhancement of HuLuc63 induced ADCC against MM cellswhen effector cells were pretreated with lenalidomide;

FIGS. 4A-4D depict the effect of bortezomib pre-treatment onHuLuc63-mediated ADCC in vitro. Examples are shown for 4 differentdonors; and,

FIGS. 5A-5B depict the effect of HuLuc63 and bortezomib in OPM2tumor-bearing mice.

5. DETAILED DESCRIPTION

The compositions described herein combine anti-CS1 antibodies with oneor more therapeutic agents at specific doses to potentiate or complementthe anti-myeloma activities of the other. Examples of suitable anti-CS1antibodies include, but are not limited to, isolated antibodies thatbind one or more of the three epitope clusters identified on CS1 andmonoclonal antibodies produced by the hybridoma cell lines: Luc2, Luc3,Luc15, Luc22, Luc23, Luc29, Luc32, Luc34, Luc35, Luc37, Luc38, Luc39,Luc56, Luc60, Luc63, Luc69, LucX.1, LucX.2 or Luc90. These monoclonalantibodies are named as the antibodies: Luc2, Luc3, Luc15, Luc22, Luc23,Luc29, Luc32, Luc34, Luc35, Luc37, Luc38, Luc39, Luc56, Luc60, Luc63,Luc69, LucX and Luc90, respectively, hereafter. Humanized versions aredenoted by the prefix “hu” (see, e.g., U.S. Patent Publication Nos.2005/0025763 and 2006/0024296, the contents of which are incorporatedherein by reference).

In some embodiments, suitable anti-CS1 antibodies include isolatedantibodies that bind one or more of the three epitope clustersidentified on CS1 (SEQ ID NO: 1, Table 1 below; see, e.g., U.S. PatentPublication No. 2006/0024296, the content of which is incorporatedherein by reference). As disclosed in U.S. Patent Publication No.2006/0024296 and shown below in Table 1, the CS1 antibody binding siteshave been grouped into 3 epitope clusters:

-   -   (1) the epitope defined by Luc90, which binds to hu50/mu50 (SEQ        ID NO: 2). This epitope covers from about amino acid residue 23        to about amino acid residue 151 of human CS1. This epitope is        resided within the domain 1 (V domain) of the extracellular        domain. This epitope is also recognized by Luc34, LucX        (including LucX.1 and LucX.2) and Luc69.    -   (2) the epitope defined by Luc38, which binds to mu25/hu75 (SEQ        ID NO: 3) and hu50/mu50 (SEQ ID NO: 81). This epitope likely        covers from about amino acid residue 68 to about amino acid        residue 151 of human CS1. This epitope is also recognized by        Luc5.    -   (3) the epitope defined by Luc 63, which binds to mu75/hu25 (SEQ        ID NO: 4). This epitope covers from about amino acid residue 170        to about amino acid residue 227 of human CS1. This epitope is        resided within domain 2 (C2 domain) of human CS1. This epitope        is also recognized by Luc4, Luc12, Luc23, Luc29, Luc32 and        Luc37.

The methods and pharmaceutical compositions are addressed in more detailbelow, but typically include at least one anti-CS1 antibody as describedabove. In some embodiments, the pharmaceutical compositions include theanti-CS1 antibody HuLuc63. HuLuc63 is a humanized recombinant monoclonalIgG1 antibody directed to human CS1. The amino acid sequence for theheavy chain variable region (SEQ ID NO: 5) and the light chain variableregion (SEQ ID NO: 6) for HuLuc63 is disclosed in U.S. PatentPublication No. 2005/0025763, the content of which is incorporatedherein by reference, and in Table 1.

TABLE 1 SEQ ID NO: Amino Acid Sequence SEQ IDMet Ala Gly Ser Pro Thr Cys Leu Thr NO: 1Leu Ile Tyr Ile Leu Trp Gln Leu Thr Gly Ser Ala Ala Ser Gly Pro Val LysGlu Leu Val Gly Ser Val Gly Gly Ala Val Thr Phe Pro Leu Lys Ser Lys ValLys Gln Val Asp Ser Ile Val Trp Thr Phe Asn Thr Thr Pro Leu Val Thr IleGln Pro Glu Gly Gly Thr Ile Ile Val Thr Gln Asn Arg Asn Arg Glu Arg ValAsp Phe Pro Asp Gly Gly Tyr Ser Leu Lys Leu Ser Lys Leu Lys Lys Asn AspSer Gly Ile Tyr Tyr Val Gly Ile Tyr Ser Ser Ser Leu Gln Gln Pro Ser ThrGln Glu Tyr Val Leu His Val Tyr Glu His Leu Ser Lys Pro Lys Val Thr MetGly Leu Gln Ser Asn Lys Asn Gly Thr Cys Val Thr Asn Leu Thr Cys Cys MetGlu His Gly Glu Glu Asp Val Ile Tyr Thr Trp Lys Ala Leu Gly Gln Ala AlaAsn Glu Ser His Asn Gly Ser Ile Leu Pro Ile Ser Trp Arg Trp Gly Glu SerAsp Met Thr Phe Ile Cys Val Ala Arg Asn Pro Val Ser Arg Asn Phe Ser SerPro Ile Leu Ala Arg Lys Leu Cys Glu Gly Ala Ala Asp Asp Pro Asp Ser SerMet Val Leu Leu Cys Leu Leu Leu Val Pro Leu Leu Leu Ser Leu Phe Val LeuGly Leu Phe Leu Trp Phe Leu Lys Arg Glu Arg Gln Glu Glu Tyr Ile Glu GluLys Lys Arg Val Asp Ile Cys Arg Glu Thr Pro Asn Ile Cys Pro His Ser GlyGlu Asn Thr Glu Tyr Asp Thr Ile Pro His Thr Asn Arg Thr Ile Leu Lys GluAsp Pro Ala Asn Thr Val Tyr Ser Thr Val Glu Ile Pro Lys Lys Met Glu AsnPro His Ser Leu Leu Thr Met Pro Asp Thr Pro Arg Leu Phe Ala Tyr Glu AsnVal Ile SEQ ID Met Ala Gly Ser Pro Thr Cys Leu Thr NO: 2Leu Ile Tyr Ile Leu Trp Gln Leu Thr Gly Ser Ala Ala Ser Gly Pro Val LysGlu Leu Val Gly Ser Val Gly Gly Ala Val Thr Phe Pro Leu Lys Ser Lys ValLys Gln Val Asp Ser Ile Val Trp Thr Phe Asn Thr Thr Pro Leu Val Thr IleGln Pro Glu Gly Gly Thr Ile Ile Val Thr Gln Asn Arg Asn Arg Glu Arg ValAsp Phe Pro Asp Gly Gly Tyr Ser Leu Lys Leu Ser Lys Leu Lys Lys Asn AspSer Gly Ile Tyr Tyr Val Gly Ile Tyr Ser Ser Ser Leu Gln Gln Pro Ser ThrGln Glu Tyr Val Leu His Val Tyr Glu His Leu Ser Lys Pro Lys Val Thr IleAsp Arg Gln Ser Asn Lys Asn Gly Thr Cys Val Ile Asn Leu Thr Cys Ser ThrAsp Gln Asp Gly Glu Asn Val Thr Tyr Ser Trp Lys Ala Val Gly Gln Gly AspAsn Gln Phe His Asp Gly Ala Thr Leu Ser Ile Ala Trp Arg Ser Gly Glu LysAsp Gln Ala Leu Thr Cys Met Ala Arg Asn Pro Val Ser Asn Ser Phe Ser ThrPro Val Phe Pro Gln Lys Leu Cys Glu Asp Ala Ala Thr Asp Leu Thr Ser LeuArg Gly SEQ ID Met Ala Arg Phe Ser Thr Tyr Ile Ile NO: 3Phe Thr Ser Val Leu Cys Gln Leu Thr Val Thr Ala Ala Ser Gly Thr Leu LysLys Val Ala Gly Ala Leu Asp Gly Ser Val Thr Phe Thr Leu Asn Ile Thr GluIle Lys Val Asp Tyr Val Val Trp Thr Phe Asn Thr Phe Phe Leu Ala Met ValLys Lys Asp Gly Gly Thr Ile Ile Val Thr Gln Asn Arg Asn Arg Glu Arg ValAsp Phe Pro Asp Gly Gly Tyr Ser Leu Lys Leu Ser Lys Leu Lys Lys Asn AspSer Gly Ile Tyr Tyr Val Gly Ile Tyr Ser Ser Ser Leu Gln Gln Pro Ser ThrGln Glu Tyr Val Leu His Val Tyr Glu His Leu Ser Lys Pro Lys Val Thr MetGly Leu Gln Ser Asn Lys Asn Gly Thr Cys Val Thr Asn Leu Thr Cys Cys MetGlu His Gly Glu Glu Asp Val Ile Tyr Thr Trp Lys Ala Leu Gly Gln Ala AlaAsn Glu Ser His Asn Gly Ser Ile Leu Pro Ile Ser Trp Arg Trp Gly Glu SerAsp Met Thr Phe Ile Cys Val Ala Arg Asn Pro Val Ser Arg Asn Phe Ser SerPro Ile Leu Ala Arg Lys Leu Cys Glu Gly Ala Ala Asp Asp Pro Asp Ser SerMet Val SEQ ID Met Ala Arg Phe Ser Thr Tyr Ile Ile NO: 4Phe Thr Ser Val Leu Cys Gln Leu Thr Val Thr Ala Ala Ser Gly Thr Leu LysLys Val Ala Gly Ala Leu Asp Gly Ser Val Thr Phe Thr Leu Asn Ile Thr GluIle Lys Val Asp Tyr Val Val Trp Thr Phe Asn Thr Phe Phe Leu Ala Met ValLys Lys Asp Gly Val Thr Ser Gln Ser Ser Asn Lys Glu Arg Ile Val Phe ProAsp Gly Leu Tyr Ser Met Lys Leu Ser Gln Leu Lys Lys Asn Asp Ser Gly AlaTyr Arg Ala Glu Ile Tyr Ser Thr Ser Ser Gln Ala Ser Leu Ile Gln Glu TyrVal Leu His Val Tyr Lys His Leu Ser Arg Pro Lys Val Thr Ile Asp Arg GlnSer Asn Lys Asn Gly Thr Cys Val Ile Asn Leu Thr Cys Ser Thr Asp Gln AspGly Glu Asn Val Thr Tyr Ser Trp Lys Ala Val Gly Gln Ala Ala Asn Glu SerHis Asn Gly Ser Ile Leu Pro Ile Ser Trp Arg Trp Gly Glu Ser Asp Met ThrPhe Ile Cys Val Ala Arg Asn Pro Val Ser Arg Asn Phe Ser Ser Pro Ile LeuAla Arg Lys Leu Cys Glu Gly Ala Ala Asp Asp Pro Asp Ser Ser Met ValSEQ ID Glu Val Gln Leu Val Glu Ser Gly Gly NO: 5Gly Leu Val Gln Pro Gly Gly Ser Leu Arg Leu Ser Cys Ala Ala Ser Gly PheAsp Phe Ser Arg Tyr Trp Met Ser Trp Val Arg Gln Ala Pro Gly Lys Gly LeuGlu Trp Ile Gly Glu Ile Asn Pro Asp Ser Ser Thr Ile Asn Tyr Ala Pro SerLeu Lys Asp Lys Phe Ile Ile Ser Arg Asp Asn Ala Lys Asn Ser Leu Tyr LeuGln Met Asn Ser Leu Arg Ala Glu Asp Thr Ala Val Tyr Tyr Cys Ala Arg ProAsp Gly Asn Tyr Trp Tyr Phe Asp Val Trp Gly Gln Gly Thr Leu Val Thr ValSer Ser SEQ ID Asp Ile Gln Met Thr Gln Ser Pro Ser NO: 6Ser Leu Ser Ala Ser Val Gly Asp Arg Val Thr Ile Thr Cys Lys Ala Ser GlnAsp Val Gly Ile Ala Val Ala Trp Tyr Gln Gln Lys Pro Gly Lys Val Pro LysLeu Leu Ile Tyr Trp Ala Ser Thr Arg His Thr Gly Val Pro Asp Arg Phe SerGly Ser Gly Ser Gly Thr Asp Phe Thr Leu Thr Ile Ser Ser Leu Gln Pro GluAsp Val Ala Thr Tyr Tyr Cys Gln Gln Tyr Ser Ser Tyr Pro Tyr Thr Phe GlyGln Gly Thr Lys Val Glu Ile Lys

At some doses, additive effects are seen; at other doses, synergisticeffects are seen. In some embodiments, the synergistic effect permitsone or more therapeutic agents to be administered in combination withone or more anti-CS1 antibodies at a reduced dosage, while retainingefficacy. Given that the side effects associated with the use of theseagents are dose-dependent, use of the compositions and methods describedherein can reduce the deleterious side effects observed in conventionaland novel treatment regimens used to treat MM when these agents areadministered at their recommended dosages.

In other embodiments, the synergistic effect permits one or moretherapeutic agents to be administered in combination with one or moreanti-CS1 antibodies at the approved dosage, but with greater than theexpected efficacy.

The compositions can be administered for the treatment of MonoclonalGammopathy of Undetermined Significance (MGUS), smoldering myeloma,asymptomatic MM, and symptomatic MM, ranging from newly diagnosed tolate stage relapsed/refractory. Typically, administration of thecompositions results in a reduction in M-protein in serum or urine suchthat a plateau, no change, minimal, partial or complete response isobserved as defined by the European Group for Blood and Marrowtransplantation (EBMT).

5.2 Pharmaceutical Compositions

Provided herein are pharmaceutical compositions that are beneficial inreducing tumor mass and/or regressing tumor growth, in patientsdiagnosed with multiple myeloma. The components of the pharmaceuticalcompositions are addressed in more detail below, but typically includean anti-CS1 antibody, such as HuLuc63 and one or more therapeuticagents. In some embodiments, the various components of the compositionsare provided separately. For example, an anti-CS1 antibody can beprovided in a first pharmaceutical composition, and a therapeutic agentprovided in a second composition. When the composition comprises two ormore therapeutic agents, an anti-CS1 antibody can be provided in a firstpharmaceutical composition, one therapeutic agent can be provided in asecond composition and the other therapeutic agent can be provided in athird composition. In other embodiments, an anti-CS1 antibody can beprovided in one pharmaceutical composition and the therapeutic agentscan be combined and provided in a second pharmaceutical composition. Instill other embodiments, one composition, comprising an anti-CS1antibody combined with one or more therapeutic agents can be provided.

In typical embodiments, an anti-CS1 antibody is present in apharmaceutical composition at a concentration sufficient to permitintravenous administration at 0.5 mg/kg to 20 mg/kg. In someembodiments, the concentration of HuLuc63 suitable for use in thecompositions and methods described herein includes, but is not limitedto, at least about 0.5 mg/kg, at least about 0.75 mg/kg, at least about1 mg/kg, at least about 2 mg/kg, at least about 2.5 mg/kg, at leastabout 3 mg/kg, at least about 4 mg/kg, at least about 5 mg/kg, at leastabout 6 mg/kg, at least about 7 mg/kg, at least about 8 mg/kg, at leastabout 9 mg/kg, at least about 10 mg/kg, at least about 11 mg/kg, atleast about 12 mg/kg, at least about 13 mg/kg, at least about 14 mg/kg,at least about 15 mg/kg, at least about 16 mg/kg, at least about 17mg/kg, at least about 18 mg/kg, at least about 19 mg/kg, and at leastabout 20 mg/kg.

The anti-CS1 antibodies can be administered in single or multiple doseregimens. Generally, an anti-CS1 antibody is administered over a periodof time from about 1 to about 24 hours, but is typically administeredover a period of about 1 to 2 hours. Dosages can be repeated from about1 to about 4 weeks or more, for a total of 4 or more doses. Typically,dosages are repeated once every week, once every other week, or once amonth, for a minimum of 4 doses to a maximum of 52 doses.

Determination of the effective dosage, total number of doses, and lengthof treatment with an anti-CS1 antibody is well within the capabilitiesof those skilled in the art, and can be determined using a standard doseescalation study to identify the maximum tolerated dose (MTD) (see,e.g., Richardson et al., 2002, Blood, 100(9):3063-3067, the content ofwhich is incorporated herein by reference).

In some embodiments, one or more therapeutic agents are administered incombination with an anti-CS1 antibody. The agents can be administeredconcurrently, prior to, or following administration of an anti-CS1antibody.

In some embodiments, an anti-CS1 antibody is administered prior to theadministration of the therapeutic agents. For example, an anti-CS1antibody can be administered approximately 0 to 60 days prior to theadministration of the therapeutic agents. In some embodiments, ananti-CS1 antibody, such as HuLuc63, is administered from about 30minutes to about 1 hour prior to the administration of the therapeuticagents, or from about 1 hour to about 2 hours prior to theadministration of the therapeutic agents, or from about 2 hours to about4 hours prior to the administration of the therapeutic agents, or fromabout 4 hours to about 6 hours prior to the administration of thetherapeutic agents, or from about 6 hours to about 8 hours prior to theadministration of the therapeutic agents, or from about 8 hours to about16 hours prior to the administration of the therapeutic agents, or fromabout 16 hours to 1 day prior to the administration of the therapeuticagents, or from about 1 to 5 days prior to the administration of thetherapeutic agents, or from about 5 to 10 days prior to theadministration of the therapeutic agents, or from about 10 to 15 daysprior to the administration of the therapeutic agents, or from about 15to 20 days prior to the administration of the therapeutic agents, orfrom about 20 to 30 days prior to the administration of the therapeuticagents, or from about 30 to 40 days prior to the administration of thetherapeutic agents, and from about 40 to 50 days prior to theadministration of the therapeutic agents, or from about 50 to 60 daysprior to the administration of the therapeutic agents.

In some embodiments, an anti-CS1 antibody is administered concurrentlywith the administration of the therapeutic agents.

In some embodiments, an anti-CS1 antibody is administered following theadministration of the therapeutic agents. For example, an anti-CS1antibody, such as HuLuc63, can be administered approximately 0 to 60days after the administration of the therapeutic agents. In someembodiments, HuLuc63 is administered from about 30 minutes to about 1hour following the administration of the therapeutic agents, or fromabout 1 hour to about 2 hours following the administration of thetherapeutic agents, or from about 2 hours to about 4 hours following theadministration of the therapeutic agents, or from about 4 hours to about6 hours following the administration of the therapeutic agents, or fromabout 6 hours to about 8 hours following the administration of thetherapeutic agents, or from about 8 hours to about 16 hours followingthe administration of the therapeutic agents, or from about 16 hours to1 day following the administration of the therapeutic agents, or fromabout 1 to 5 days following the administration of the therapeuticagents, or from about 5 to 10 days following the administration of thetherapeutic agents, or from about 10 to 15 days following theadministration of the therapeutic agents, or from about 15 to 20 daysfollowing the administration of the therapeutic agents, or from about 20to 30 days following the administration of the therapeutic agents, orfrom about 30 to 40 days following the administration of the therapeuticagents, and from about 40 to 50 days following the administration of thetherapeutic agents, or from about 50 to 60 days following theadministration of the therapeutic agents.

The therapeutic agents can be administered in any manner foundappropriate by a clinician and are typically provided in generallyaccepted efficacious dose ranges, such as those described in thePhysician Desk Reference, 56th Ed. (2002), Publisher Medical Economics,New Jersey. In other embodiments, a standard dose escalation can beperformed to identify the maximum tolerated dose (MTD) (see, e.g.,Richardson, et al. 2002, Blood, 100(9):3063-3067, the content of whichis incorporated herein by reference).

In some embodiments, doses less than the generally accepted efficaciousdose of a therapeutic agent can be used. For example, in variousembodiments, the composition comprises a dosage that is less than about10% to 75% of the generally accepted efficacious dose range. In someembodiments, at least about 10% or less of the generally acceptedefficacious dose range is used, at least about 15% or less, at leastabout 25%, at least about 30% or less, at least about 40% or less, atleast about 50% or less, at least about 60% or less, at least about 75%or less, and at least about 90%.

The therapeutic agents can be administered singly or sequentially, or ina cocktail with other therapeutic agents, as described below. Thetherapeutic agents can be administered orally, intravenously,systemically by injection intramuscularly, subcutaneously, intrathecallyor intraperitoneally.

Examples of therapeutic agents that can be used in the compositionsdescribed herein include, but are not limited to, dexamethasone,thalidomide, melphalan, prednisone, doxorubicin, doxorubicin HCLliposome injection, bortezomib, lenalidomide, and/or combinationsthereof.

Accordingly, in some embodiments, two pharmaceutical compositions areprovided: a first comprising a therapeutically effective amount of ananti-CS1 antibody, such as HuLuc63 and a second comprising atherapeutically effective amount of lenalidomide.

In some embodiments, two pharmaceutical compositions are provided: afirst comprising a therapeutically effective amount of an anti-CS1antibody, such as HuLuc63, and a second comprising a therapeuticallyeffective amount of bortezomib.

In some embodiments, at least two pharmaceutical compositions areprovided: a first comprising a therapeutically effective amount of ananti-CS1 antibody, such as HuLuc63 and a second comprising atherapeutically effective amount of lenalidomide and a therapeuticallyeffective amount of bortezomib. In some embodiments, lenalidomide andbortezomib are provided separately, such that a total of threepharmaceutical compositions are provided: a first comprising an anti-CS1antibody, such as HuLuc63, a second comprising lenalidomide, and a thirdcomprising bortezomib.

In some embodiments, at least two pharmaceutical compositions areprovided: a first comprising a therapeutically effective amount of ananti-CS1 antibody, such as HuLuc63 and a second comprising atherapeutically effective amount of lenalidomide and dexamethasone. Insome embodiments, lenalidomide and dexamethasone are providedseparately, such that a total of three pharmaceutical compositions areprovided: a first comprising an anti-CS1 antibody, such as HuLuc63, asecond comprising lenalidomide, and a third comprising dexamethasone.

In some embodiments at least two pharmaceutical compositions areprovided: a first comprising a therapeutically effective amount of ananti-CS1 antibody, such as HuLuc63 and a second comprising atherapeutically effective amount of bortezomib and dexamethasone. Insome embodiments, bortezomib and dexamethasone are provided separately,such that a total of three pharmaceutical compositions are provided: afirst comprising an anti-CS1 antibody, such as HuLuc63, a secondcomprising bortezomib, and a third comprising dexamethasone.

In some embodiments, at least two pharmaceutical compositions areprovided: a first comprising a therapeutically effective amount of ananti-CS1 antibody, such as HuLuc63, and a second comprisingtherapeutically effective amount of lenalidomide, bortezomib, anddexamethasone. In some embodiments, lenalidomide, bortezomib, anddexamethasone are provided separately. Provided that the agents retaintheir efficacy, compositions comprising other combinations can beprepared, depending in part, on dosage, route of administration, andwhether the agents are provided in a solid, semi-solid or liquid form.For example, a total of three compositions can be made: a firstcomprising a therapeutically effective amount of an anti-CS1 antibody,such as HuLuc63, a second comprising dexamethasone, and a thirdcomprising lenalidomide and bortezomib.

In some embodiments, at least two pharmaceutical compositions areprovided: a first comprising a therapeutically effective amount of ananti-CS1 antibody, such as HuLuc63, and a second comprising atherapeutically effective amount of bortezomib and optionally cancomprise one or more of the following agents: thalidomide,dexamethasone, melphalan, doxorubicin, doxorubicin HCl liposomeinjection, and/or prednisone. Provided that the agents retain theirefficacy, compositions comprising various combinations of thalidomide,dexamethasone, melphalan, doxorubicin, doxorubicin HCl liposomeinjection, and prednisone can be prepared depending in part, on dosage,route of administration, and whether the agents are provided in a solid,semi-solid or liquid form.

The pharmaceutical compositions can exist as a solid, semi-solid, orliquid (e.g., suspensions or aerosols) dosage form. Typically, thecompositions are administered in unit dosage forms suitable for singleadministration of precise dosage amounts. For example, anti-CS1antibodies can be packaged in dosages ranging from about 1 to 1000 mg.In some embodiments, anti-CS1 antibodies can be packaged in a dosage atleast about 1 mg, at least about 10 mg, at least about 20 mg, at leastabout 50 mg, at least about 100 mg, at least about 200 mg, at leastabout 300 mg, at least about 400 mg, at least about 500 mg, at leastabout 750 mg, at least about 1000 mg.

The compositions can also include, depending on the formulation desired,pharmaceutically-acceptable, nontoxic carriers or diluents, which aredefined as vehicles commonly used to formulate pharmaceuticalcompositions for animal or human administration. The diluent is selectedso as not to affect the biological activity of the combination. Examplesof such diluents are distilled water, physiological saline, Ringer'ssolution, dextrose solution, and Hank's solution.

In addition, the pharmaceutical composition or formulation can alsoinclude other carriers, adjuvants, or nontoxic, non-therapeutic,nonimmunogenic stabilizers and the like. Effective amounts of suchdiluent or carrier will be those amounts that are effective to obtain apharmaceutically acceptable formulation in terms of solubility ofcomponents, or biological activity.

5.3 Methods

The pharmaceutical compositions described herein find use in treatingMM. Typically, the compositions can be used to treat MonoclonalGammopathy of Undetermined Significance (MGUS), smoldering myeloma,asymptomatic MM, and symptomatic MM, ranging from newly diagnosed tolate stage relapsed/refractory.

The compositions can be combined with other treatment strategies, i.e.,autologous stem cell transplantation and allogeneic effector celltransplantation, to develop an effective treatment strategy based on thestage of myeloma being treated (see, e.g., Multiple Myeloma ResearchFoundation, Multiple Myeloma: Stem Cell Transplantation 1-30 (2004);U.S. Pat. Nos. 6,143,292, and 5,928,639, Igarashi, et al. Blood 2004,104(1): 170-177, Maloney, et al. 2003, Blood, 102(9): 3447-3454, Badros,et al. 2002, J Clin Oncol., 20:1295-1303, Tricot, et al. 1996, Blood,87(3):1196-1198; the contents of which are incorporated herein byreference).

The staging system most widely used since 1975 has been the Dune-Salmonsystem, in which the clinical stage of disease (Stage I, II, or III) isbased on four measurements (see, e.g., Durie and Salmon, 1975, Cancer,36:842-854). These four measurements are: (1) levels of monoclonal (M)protein (also known as paraprotein) in the serum and/or the urine; (2)the number of lytic bone lesions; (3) hemoglobin values; and, (4) serumcalcium levels. These three stages can be further divided according torenal function, classified as A (relatively normal renal function, serumcreatinine value <2.0 mg/dL) and B (abnormal renal function, creatininevalue ≧2.0 mg/dL). A new, simpler alternative is the InternationalStaging System (ISS) (see, e.g., Greipp et al., 2003, “Development of aninternational prognostic index (IPI) for myeloma: report of theinternational myeloma working group”, The Hematology). The ISS is basedon the assessment of two blood test results, beta₂-microglobulin (β₂-M)and albumin, which separates patients into three prognostic groupsirrespective of type of therapy.

Administration of the pharmaceutical compositions at selected dosageranges and routes typically elicits a beneficial response as defined bythe European Group for Blood and Marrow transplantation (EBMT). Table 2lists the EBMT criteria for response.

TABLE 2 EBMT/IBMTR/ABMTR¹ Criteria for Response Complete Response NoM-protein detected in serum or urine by immunofixation for a minimum of6 weeks and fewer than 5% plasma cells in bone marrow PartialResponse >50% reduction in serum M-protein level and/or 90% reduction inurine free light chain excretion or reduction to <200 mg/24 hrs for 6weeks² Complete Response No M-protein detected in serum or urine byimmunofixation for a minimum of 6 weeks and fewer than 5% plasma cellsin bone marrow Minimal Response 25-49% reduction in serum M-proteinlevel and/or 50-89% reduction in urine free light chain excretion whichstill exceeds 200 mg/24 hrs for 6 weeks³ No Change Not meeting thecriteria or either minimal response or progressive disease Plateau Noevidence of continuing myeloma-related organ or tissue damage, <25%change in M- protein levels and light chain excretion for 3 monthsProgressive Disease Myeloma-related organ or tissue damage continuingdespite therapy or its reappearance in plateau phase, >25% increase inserum M- protein level (>5 g/L) and/or >25% increase in urine M-proteinlevel (>200 mg/24 hrs) and/or >25% increase in bone marrow plasma cells(at least 10% in absolute terms)² Relapse Reappearance of disease inpatients previously in complete response, including detection ofparaprotein by immunofixation ¹EBMT: European Group for Blood and Marrowtransplantation; IBMTR: International Bone Marrow Transplant Registry;ABMTR: Autologous Blood and Marrow Transplant Registry. ²For patientswith non-secretory myeloma only, reduction of plasma cells in the bonemarrow by >50% of initial number (partial response) or 25-49% of initialnumber (minimal response) is required. ³In non-secretory myeloma, bonemarrow plasma cells should increase by >25% and at least 10% in absoluteterms; MRI examination may be helpful in selected patients.

Additional criteria that can be used to measure the outcome of atreatment include “near complete response” and “very good partialresponse”. A “near complete response” is defined as the criteria for a“complete response” (CR), but with a positive immunofixation test. A“very good partial response” is defined as a greater than 90% decreasein M protein (see, e.g., Multiple Myeloma Research Foundation, MultipleMyeloma: Treatment Overview 9 (2005)).

The degree to which administration of the compositions elicits aresponse in an individual clinically manifesting at least one symptomassociated with MM, depends in part, on the severity of disease, e.g.,Stage I, II, or III, and in part, on whether the patient is newlydiagnosed or has late stage refractory MM. Thus, in some embodiments,administration of the pharmaceutical composition elicits a completeresponse.

In other embodiments, administration of the pharmaceutical compositionelicits a very good partial response or a partial response.

In other embodiments, administration of the pharmaceutical compositionelicits a minimal response.

In other embodiments, administration of the pharmaceutical compositionprevents the disease from progressing, resulting in a responseclassified as “no change” or “plateau” by the EBMT.

Routes of administration and dosage ranges for compositions comprisingan anti-CS1 antibody and one or more therapeutic agents for treatingindividuals diagnosed with MM, can be determined using art-standardtechniques, such as a standard dose escalation study to identify the MTD(see, e.g., Richardson, et al. 2002, Blood, 100(9):3063-3067, thecontent of which is incorporated herein by reference).

Typically, anti-CS1 antibodies are administered intravenously.Administration of the other therapeutic agents described herein can beby any means known in the art. Such means include oral, rectal, nasal,topical (including buccal and sublingual) or parenteral (includingsubcutaneous, intramuscular, intravenous and intradermal) administrationand will depend in part, on the available dosage form. For example,therapeutic agents that are available in a pill or capsule formattypically are administered orally. However, oral administrationgenerally requires administration of a higher dose than does intravenousadministration. Determination of the actual route of administration thatis best in a particular case is well within the capabilities of thoseskilled in the art, and in part, will depend on the dose needed versusthe number of times per month administration is required.

Factors affecting the selected dosage of an anti-CS1 antibody and thetherapeutic agents used in the compositions and methods describedherein, include, but are not limited to, the type of agent, the age,weight, and clinical condition of the recipient patient, and theexperience and judgment of the clinician or practitioner administeringthe therapy. Generally, the selected dosage should be sufficient toresult in no change, but preferably results in at least a minimalchange. An effective amount of a pharmaceutical agent is that whichprovides an objectively identifiable response, e.g., minimal, partial,or complete, as noted by the clinician or other qualified observer, andas defined by the EBMT.

Generally, an anti-CS1 antibody, such as HuLuc63, is administered as aseparate composition from the composition(s) comprising the therapeuticagents. As discussed above, the therapeutic agents can each beadministered as a separate composition, or combined in a cocktail andadministered as a single combined composition. In some embodiments, thecompositions comprising an anti-CS1 antibody and one or more therapeuticagents are administered concurrently. In other embodiments, an anti-CS1antibody can be administered prior to the administration ofcomposition(s) comprising the therapeutic agent(s). In yet otherembodiments, an anti-CS1 antibody is administered following theadministration of composition(s) comprising the therapeutic agent(s).

In those embodiments in which an anti-CS1 antibody is administered priorto or following the administration of the therapeutic agents,determination of the duration between the administration of an anti-CS1antibody and administration of the agents is well within thecapabilities of those skilled in the art, and in part, will depend onthe dose needed versus the number of times per month administration isrequired.

Doses of anti-CS1 antibodies used in the methods described hereintypically range between 0.5 mg/kg to 20 mg/kg. Optimal doses for thetherapeutic agents are the generally accepted efficacious doses, such asthose described in the Physician Desk Reference, 56th Ed. (2002),Publisher Medical Economics, New Jersey. Optimal doses for agents notdescribed in the Physician Desk Reference can be determined using astandard dose escalation study to identify the MTD (see, e.g.,Richardson, et al. 2002, Blood, 100(9):3063-3067, the contents of whichare incorporated herein by reference).

In some embodiments, an anti-CS1 antibody is present in a pharmaceuticalcomposition at a concentration, or in a weight/volume percentage, or ina weight amount, suitable for intravenous administration at a dosagerate at least about 0.5 mg/kg, at least about 0.75 mg/kg, at least about1 mg/kg, at least about 2 mg/kg, at least about 2.5 mg/kg, at leastabout 3 mg/kg, at least about 4 mg/kg, at least about 5 mg/kg, at leastabout 6 mg/kg, at least about 7 mg/kg, at least about 8 mg/kg, at leastabout 9 mg/kg, at least about 10 mg/kg, at least about 11 mg/kg, atleast about 12 mg/kg, at least about 13 mg/kg, at least about 14 mg/kg,at least about 15 mg/kg, at least about 16 mg/kg, at least about 17mg/kg, at least about 18 mg/kg, at least about 19 mg/kg, and at leastabout 20 mg/kg.

6. EXAMPLES Example 1 HuLuc63 in Combination with Lenalidomide

Lenalidomide is the first of a new class of oral cancer drugs calledIMiDs®. These immunomodulatory derivatives are chemically similar tothalidomide but are more potent and have a different side effect profilethan thalidomide. They have multiple mechanisms of action that affectboth the cancer cell and its microenvironment. Lenalidomide has beenshown to induce immune responses, enhance activity of immune cells, andinhibit inflammation. For example, lenalidomide may enhance theactivation of T cells and NK cells, induce production of interleukin 2and inhibit pro-inflammatory cytokines such as tumor necrosisfactor-alpha and interleukin 1-beta. Currently lenalidomide incombination with dexamethasone is approved for 2^(nd) line therapy ofmultiple myeloma.

In Vitro ADCC Assay: Methods and Results

ADCC was measured by calcein-AM release assay, with sensitivity similarto traditional Cr⁵¹ assay, as described previously. After informedconsent, peripheral blood mononuclear cells (PBMCs) including naturalkiller (NK) effector cells were isolated from leukopheresis products ofnormal donors or peripheral blood from MM patients. Increasingconcentrations (0-10 μg/ml) of either HuLuc63 or human isotype controlIgG₁ MSL109 mAbs were added at effector:target (E:T) ratios of 20:1, ina final volume of 200 n1 per well. In some experiments, PBMC effectorcells were pretreated with lenalidomide for 3 days at 0.2 μM beforeHuLuc63-mediated ADCC assays were performed. After 4 h incubation, 100n1 culture supernatants were transferred to a Black ViewPlate™-96 plateand arbitrary fluorescent units (AFU) were read on a fluorometer (WallacVICTOR2). This assay is valid only if (AFU mean maximum release−mediumcontrol release)/(AFU mean spontaneous release−medium controlrelease) >7. Calculation of % specific lysis from triplicate experimentswas done using the following equation:

$\mspace{20mu} {{\% \mspace{14mu} {Specific}\mspace{14mu} {Lysis}} = {100 \times \frac{\begin{pmatrix}{{{AFU}\mspace{14mu} {mean}\mspace{14mu} {experimental}\mspace{14mu} {release}} -} \\{{AFU}\mspace{14mu} {mean}\mspace{14mu} {spontaneous}\mspace{14mu} {release}^{1}}\end{pmatrix}}{\begin{pmatrix}{{{AFU}\mspace{14mu} {mean}\mspace{14mu} {maximal}\mspace{14mu} {release}^{2}} -} \\{{AFU}\mspace{14mu} {mean}\mspace{14mu} {spontaneous}\mspace{14mu} {release}}\end{pmatrix}}}}$ ¹Calcein-AM  release  by  target  cells  in  the  absence  of  Ab  or  NK  cells. ²Calcein-AM  release  by  target  cells  upon  lysis  by  detergent.

HuLuc63-mediated lysis of patient MM cells by effector cells from thesame patient was measured using an ADCC assay. HuLuc63, but not isoIgG₁, induced significant autologous myeloma cell lysis in patients inpatient samples (FIGS. 1A-1C). HuLuc63-mediated autologous tumor celllysis was also demonstrated in patients with MM resistant or refractoryto novel anti-MM therapies including bortezomib and/or 17-AAG (targetingheat shock protein 90) (FIGS. 2A and 2B). These data suggest thatHuLuc63 can target myeloma cells from patients that are newly diagnosed,or resistant to standard of care drugs and/or novel agents.

HuLuc63-mediated lysis of patient myeloma cells by PBMC effector cellsfrom the same patient was measured using an ADCC assay. CD138-purifiedtumor cells from a patient with MM were incubated with autologouseffector cells in the presence of serial dilutions of HuLuc63 (solidsymbols) or isotype control IgG₁ (open symbols). PBMC effector cellswere pre-incubated for 3 days in the presence or absence of withlenalidomide (0.2 mM) (square symbols) or vehicle control (roundsymbols), followed by HuLuc63-mediated ADCC. HuLuc63-mediated ADCC, butnot iso IgG₁, induced significant autologous myeloma cell lysis in apatient sample. Pre-incubation of the PBMC effector cells withlenalidomide significantly increased the ADCC activity (FIG. 3C).Similarly, pretreatment of effector cells with lenalidomide enhancedHuLuc63-induced lysis of myeloma cell lines (FIGS. 3A and 3B). Theseresults provide the framework for a treatment strategy combininglenalidomide with HuLuc63 in MM.

Example 2 HuLuc63 in Combination with Bortezomib

Bortezomib is a potent, specific, and reversible proteasome inhibitor.Proteasomes are present in all cells and function to help regulate cellgrowth. Inhibition of the proteasome results in apoptosis of cancercells. Bortezomib has been shown to be particularly effective at killingmyeloma cells and is currently approved for 2^(nd) and 3^(rd) linetherapy in multiple myeloma. Recent data has shown that bortezomibtreatment of myeloma cells results in down-modulation of cell-surfaceexpression of MHC class I, an inhibitor of NK function (Shi et al.,Blood (ASH Annual Meeting Abstracts), November 2006; 108:3498). Thehypothesis is that bortezomib treatment of myeloma cells would make themmore susceptible to NK-mediated killing and, thus, enhanceHuLuc63-mediated ADCC. The purpose of this study was to examine whetherusing HuLuc63 in combination with bortezomib provided therapeuticbenefit.

The effect of HuLuc63 and bortezomib treatment on expression of CS1 inMM cell lines and mouse xenograft tumors was examined by flow cytometryand immunohistochemistry respectively.

In vitro ADCC Assay: Methods and Results

OPM2 myeloma cells were harvested at mid-log phase, suspended at adensity of 1.0×10⁶ cells/mL in complete media (RPMI with 10% FBS) andtreated overnight with or without Velcade (10 nM). Cells were collected,washed, re-suspended at a density of 20×106 viable cells/mL, and labeledfor one hour with 50 mCi Na₂[⁵¹Cr]O₄ per 10⁶ cells. ⁵¹Cr-Labeled cellswere washed then added to a 96-well V-bottomed polystyrene plate at acell density of 15,000 cells per 75 μL RPMI supplemented with 10%heat-inactivated

FBS. HuLuc63 and a human IgG₁ isotype control antibody MSL-109 wereadded to target cells for a final antibody concentration ranging from0.001 to 10 μg/mL. NK cells were enriched from the whole blood ofhealthy donors using the RosetteSep human NK cell enrichment cocktail(Stem Cell Technologies). The enriched NK cells were added to Velcadetreated or untreated OPM2 cells at a ratio of 10:1. After a 4-hourincubation at 3TC, cells were centrifuged and the supernatants measuredfor released ⁵¹Cr. Maximum release was determined from target cellslysed with 100 mg/ml Digitonin. Antibody independent cellularcytotoxicity (AICC) was determined using target cells, plus media, plusNK cells, while spontaneous lysis was determined using ⁵¹Cr-labelledcells plus media without NK effectors.

% Cytotoxicity was calculated as ((sample−AICC)/(Maximum−AICC)*100.

CS1 protein expression was examined on the OPM2 multiple myeloma cellline with no significant change in CS1 expression observed pre- orpost-treatment with HuLuc63, bortezomib or with both agents. Thecombination of HuLuc63 with bortezomib was then tested for anti-myelomaactivity in vitro using ADCC assays. The results showed thatpre-treatment with bortezomib significantly enhanced HuLuc63-mediatedADCC towards OPM2 cells using NK effector cells from healthy donors.OPM2 cells were pretreated with vehicle control (square symbols) orbortezomib (10 nM; round symbols) for 18 hrs and were then subjected toHuLuc63 mediated ADCC using human NK cells from healthy donors. HuLuc63(closed symbols) and isotype control antibody (open symbols) were usedat doses ranging from 0.001-10 μg/ml. The results show that bortezomibpre-treatment significantly decreased the EC₅₀ for HuLuc63-mediated ADCCin vitro (FIGS. 4A-4D, Table 3).

TABLE 3 Bortezomib P value No Treatment (10 nM) (t test) 1 0.0758 0.01060.04 2 0.149 0.057 0.05 3 0.103 0.0459 0.004 4 0.0302 0.0207 0.0004

In Vivo Xenograft Mouse Model: Methods and Results

Six- to eight-week old female IcrTac:ICR-Prkdc^(scid) mice obtained fromTaconic Farms (Germantown, N.Y.) were inoculated with 1×10⁷ OPM2(American Type Culture Collection) cells into the lower right flank.Caliper measurements were performed twice weekly to calculate tumorvolume using the following formula: L×W×H/2, where L (length) is thelongest side of the tumor in the plane of the animal's back, W (width)is the longest measurement perpendicular to the length and in the sameplane and H (height) is taken at the highest point perpendicular to theback of the animal. When tumors reached an average size of about 100mm³, animals were randomized into 3 groups of 8-10 mice each and weretreated with 1 mg/kg of antibody administered intraperitoneally twice aweek for a total of 6 doses. Bortezomib was administeredintraperitoneally at a dose of 0.75 mg/kg twice a week for a total of 6doses. Tumor growth was monitored for a period of 1-2 months. Animalwork was carried out under NIH guidelines (“Guide for the Care and Useof Laboratory Animals”) using protocols approved by IACUC at PDLBioPharma.

To examine the effect of HuLuc63 combination therapy with bortezomib invivo, OPM2 tumor-bearing mice were treated with sub-optimal doses ofHuLuc63 (1 mg/kg), or isotype control antibody twice weekly for threeweeks. Bortezomib was given twice a week at 0.75 mg/kg to mice receivingeither isotype control antibody or HuLuc63. The results showedsignificant anti-tumor activity of HuLuc63 alone and in combination withbortezomib (FIG. 5A). Mice in the combination treatment group exhibitedon average 40-50% smaller tumors than in the HuLuc63 monotherapy group,and 60-70% smaller tumors than in the bortezomib group.

In a second experiment, HuLuc63 was combined with bortezomib in vivo,using a different dose and dosing schedule for bortezomib, while keepingthe original HuLuc63 dose and dosing schedule. OPM2 cells wereinoculated into the flanks of SCID mice. When tumors reached an averagesize of about 100 mm3, animals were randomized into 4 groups of 15 miceeach and were treated with 1 mg/kg of antibody administeredintraperitoneally twice a week for a total of 10 doses. Bortezomib wasadministered intraperitoneally at a dose of 1 mg/kg twice for weeks 1and 2, no treatment for week 3, and 1 mg/kg twice for weeks 4 and 5 fora total of 8 doses. The intent for this dosing schedule was to moreclosely mimic the dosing schedule of bortezomib in the clinic, whereeach treatment cycle consists of 2 weeks of dosing, with one week off.Tumor growth was monitored for a period of 1-2 months.

The results showed significant anti-tumor activity of HuLuc63 alone,bortezomib alone and for HuLuc63 in combination with bortezomib (FIG.5B). Mice in the combination treatment group exhibited significantlysmaller tumors than mice treated with either drug alone. The dataindicates that bortezomib synergizes with HuLuc63 in anti-myeloma tumoractivity.

Example 3 Phase 1b, Open-Label, Dose-Escalation Study of HuLuc63 andBortezomib in Multiple Myeloma Patients Following First or SecondRelapse

The proposed Phase 1b, multi-center, open-label, multi-dose, doseescalation study will evaluate the combination of HuLuc63 and bortezomibin patients with multiple myeloma after 1st or 2nd relapse. HuLuc63 willbe given by intravenous injection (IV) at up to five dose levels rangingfrom 2.5 mg/kg to 20 mg/kg in combination with a fixed dose ofbortezomib IV at 1.0 mg/m2. Patients will receive HuLuc63 every 10 daysand bortezomib will be given in 21-day cycles (twice weekly for twoweeks (days 1, 4, 8, 11) followed by a 10-day rest period (days 12-21)).

After 9 weeks of therapy (6 doses of HuLuc63, 3 cycles of bortezomib),EBMT criteria will be assessed. If a patient has progressive disease,HuLuc63 will be discontinued and bortezomib may be withdrawn orcontinued at the discretion of the site investigator. If the patient hasresponded or has stable disease at Week 9, dosing with HuLuc63 andbortezomib will continue so that a total of 24 weeks of treatment (16doses HuLuc63, 8 cycles bortezomib) are completed or disease progressionoccurs. Dosing with HuLuc63 and bortezomib will continue until the datafrom the Week 9 visit are available.

Patients will receive HuLuc63 IV once every 10 days, with each doseinfused over 1 hour. Bortezomib will be given as IVP for 8 three-weekcycles with each cycle consisting of bortezomib on days 1, 4, 8 and 11followed by a ten-day rest period (days 11-21). Dosing cohorts are asfollows: 2.5 mg/kg HuLuc63/1.3 mg/m² bortezomib; 5 mg/kg HuLuc63/1.3mg/m² bortezomib; 10 mg/kg HuLuc63/1.3 mg/m² bortezomib; 15 mg/kgHuLuc63/1.3 mg/m² bortezomib; and, 20 mg/kg HuLuc63/1.3 mg/m²bortezomib.

HuLuc63 will be provided at a concentration of 10 mg/mL in anintravenous formulation in vials. Bortezomib will be provided as a 3.5mg lyophilized cake or powder in a 10 mL vial, to be reconstituted with3.5 mL normal (0.9%) saline, sodium chloride injection to 3.5 mL of 1mg/mL of bortezomib, as per Velcade® package insert.

Approximately 15 to 30 patients in 5 cohorts will be enrolled in thetrial. Each cohort will begin with 3 patients. If no dose-limitingtoxicity (DLT) is noted within the first 6 weeks of treatment in anypatient, enrollment will begin in the next higher cohort. If one patienthas a DLT, 3 additional patients will be enrolled in the cohort. If noother patient in the cohort has a DLT, escalation to the next cohort mayproceed. If a second patient in a cohort has a DLT, the maximumtolerated dose (MTD) has been reached.

A dose-limiting toxicity (DLT) is defined using the National CancerCenter Institute Common Toxicity Criteria Version 3.0 (NCI CTCAE v3.0)as a grade 4 hematologic toxicity or hyperbilirubinemia, or a grade 3toxicity in any other system considered related to HuLuc63 or thecombination of HuLuc63 and bortezomib. For dose escalation to the nextcohort, 3 assessable patients must complete their first 6 weeks (4 dosesHuLuc63, 2 cycles bortezomib). If a DLT occurs, an additional threeassessable patients will be accrued. Patients will be monitored forsafety by assessing adverse events categorized by NCI CTCAE v3.0 andpatients will be monitored for clinical activity using EBMT. Themaximally tolerated dose (MTD) is defined as the highest dose studiedfor which the incidence of DLTs is <33%. The highest tolerated dose willbe HuLuc63 20 mg/kg+bortezomib 1.0 mg/m² if no dose limiting toxicitiesare observed.

Example 4 Phase 1b, Multi-Center, Open-Label, Dose-Escalation Study ofHuLuc63 and Lenalidomide

The proposed Phase 1b, multi-center, open-label, multi-dose, doseescalation study will evaluate the combination of HuLuc63 andlenalidomide in patients with multiple myeloma after 1st or 2nd relapse.HuLuc63 will be given by intravenous injection (IV) at up to five doselevels ranging from 2.5 mg/kg to 20 mg/kg in combination with a fixeddose of lenalidomide PO at 15 mg. Patients will receive HuLuc63 every 7days and lenalidomide will be given in 28-day cycles (once daily for 21days followed by a 7-day rest period (days 22-28)).

After 8 weeks of therapy (8 doses of HuLuc63, 2 cycles of lenalidomide),EBMT criteria will be assessed. Dexamethasone will be added to theregimen at an oral dose of 40 mg daily on days 1, 8, 15 and 22 of a4-week cycle. If at week 12 (12 doses HuLuc63, 3 cycles of lenalidomide,1 cycle of dexamethasone) there is evidence of progressive disease,HuLuc63 will be stopped and lenalidomide and dexamethasone will becontinued up to 16 weeks at the discretion of the investigator. If apatient has stable disease or better, they will continue on HuLuc63until week 16 (15 total doses) or disease progression. EMBT criteriawill be evaluated at week 16.

Patients will receive HuLuc63 IV once every 10 days, with each doseinfused over 1 hour. Lenalidomide will be given orally daily for 3 weeksfollowed by a weeklong rest period. Dosing cohorts are as follows: 2.5mg/kg HuLuc63/15 mg lenalidomide; 5 mg/kg HuLuc63/15 mg lenalidomide; 10mg/kg HuLuc63/15 mg lenalidomide; 15 mg/kg HuLuc63/15 mg lenalidomide;and, 20 mg/kg HuLuc63/15 mg lenalidomide. After week 8, dexamethasonewill be added to the above regimens at an oral dose of 40 mg daily ondays 1, 8, 15 and 22 of a 4 week cycle.

HuLuc63 will be provided at a concentration of 10 mg/mL in anintravenous formulation in vials. Lenalidomide will be supplied as 5 mgand 10 mg capsules for oral administration.

Approximately 15 to 30 patients in 5 cohorts will be enrolled in thetrial. Each cohort will begin with 3 patients. If no dose-limitingtoxicity (DLT) is noted within the first 4 weeks of treatment in anypatient, enrollment will begin in the next higher cohort. If one patienthas a DLT, 3 additional patients will be enrolled in the cohort. If noother patient in the cohort has a DLT, escalation to the next cohort mayproceed. If a second patient in a cohort has a DLT, the maximumtolerated dose (MTD) has been reached.

A dose-limiting toxicity (DLT) is defined using the National CancerCenter Institute Common Toxicity Criteria Version 3.0 (NCI CTCAE v3.0)as a grade 4 hematologic toxicity or hyperbilirubinemia, or a grade 3toxicity in any other system considered related to HuLuc63 or thecombination of HuLuc63 and lenalidomide. For dose escalation to the nextcohort, 3 assessable patients must complete their first 4 weeks (4 dosesHuLuc63, 1 cycle lenalidomide). If a DLT occurs, an additional threeassessable patients will be accrued. Patients will be monitored forsafety by assessing adverse events categorized by NCI CTCAE v3.0 andpatients will be monitored for clinical activity using EBMT. Themaximally tolerated dose (MTD) is defined as the highest dose studiedfor which the incidence of DLTs is <33%. The highest tolerated dose willbe HuLuc63 20 mg/kg+lenalidomide 15 mg if no dose limiting toxicitiesare observed.

All publications, patents, patent applications and other documents citedin this application are hereby incorporated by reference in theirentireties for all purposes to the same extent as if each individualpublication, patent, patent application or other document wereindividually indicated to be incorporated by reference for all purposes.

While various specific embodiments have been illustrated and described,it will be appreciated that various changes can be made withoutdeparting from the spirit and scope of the invention(s).

1-63. (canceled)
 64. A method of treating multiple myeloma in a subject,comprising administering to a subject in need thereof a firstpharmaceutical composition comprising a therapeutically effective amountof an anti-CS1 antibody and a second pharmaceutical compositioncomprising a therapeutically effective amount of lenalidomide.
 65. Themethod of claim 64, wherein the anti-CS1 antibody binds the epitopecovered by amino acids 170 to 227 of SEQ ID NO:1.
 66. The method ofclaim 64, wherein the anti-CS1 antibody binds the epitope covered byamino acids 23 to 151 of SEQ ID NO:1 or the epitope covered by aminoacids 68 to 151 of SEQ ID NO:1.
 67. The method of claim 64, wherein theanti-CS1 antibody is a humanized IgG₁ antibody comprising the heavychain variable region of SEQ ID NO:5 and the light chain variable regionof SEQ ID NO:6.
 68. A method of treating multiple myeloma in a subject,the method comprising administering to a subject in need thereof (a) ananti-CS1 antibody that binds the epitope cluster covered by amino acids170 to 227 of SEQ ID NO:1, and (b) two more therapeutic agents, whereinsaid two more therapeutic agents consist of dexamethasone andbortezomib.
 69. The method of claim 68, wherein the anti-CS1 antibody,the dexamethasone and the bortezomib are provided in three separatepharmaceutical compositions.
 70. The method of claim 69, wherein thethree pharmaceutical compositions are administered separately orconcurrently.
 71. The method of claim 70, wherein the threepharmaceutical compositions are administered separately.
 72. The methodof claim 69, wherein the anti-CS1 antibody is a humanized IgG₁ antibodycomprising the heavy chain variable region of SEQ ID NO:5 and the lightchain variable region of SEQ ID NO:6.
 73. The method of claim 72, inwhich the anti-CS1 antibody is administered intravenously at a dose fromapproximately 0.5 mg/kg to approximately 20 mg/kg.
 74. The method ofclaim 72, in which the anti-CS1 antibody is administered intravenouslyat a dose of approximately 10 mg/kg.
 75. The method of claim 72, whereinthe bortezomib is administered twice weekly over a 21 day cycle followedby a 10 day rest period.
 76. The method of claim 72, wherein theanti-CS1 antibody administered once every 10 days.
 77. The method ofclaim 72, wherein the anti-CS1 antibody is administered as anintravenous infusion at a dose from 2.5 mg/kg to 20 mg/kg and whereinthe bortezomib is administered as an intravenous infusion at a dose from0.2 mg/m² to 2.0 mg/m².
 78. The method of claim 77, wherein thebortezomib is administered at an intravenous dose from 1.0 mg/m² to 1.3mg/m².
 79. The method of claim 78, wherein the bortezomib isadministered at an intravenous dose of 1.0 mg/m².
 80. The method ofclaim 78, wherein the bortezomib is administered at an intravenous doseof 1.3 mg/m².
 81. The method of claim 77, wherein the anti-CS1 antibodyis administered at an intravenous dose of 2.5 mg/kg.
 82. The method ofclaim 77, wherein the anti-CS1 antibody is administered at anintravenous dose of 5 mg/kg.
 83. The method of claim 77, wherein theanti-CS1 antibody is administered at an intravenous dose of 10 mg/kg.84. The method of claim 77, wherein the patient receives the anti-CS1antibody once every 10 days.
 85. The method of claim 84, wherein thepatient receives the bortezomib four times in a three week cycle. 86.The method of claim 85, wherein the bortezomib is given on days 1, 4, 8,and 11 followed by a 10 day rest period.
 87. A method of treatingmultiple myeloma in a subject concurrently on a regimen of twotherapeutic agents that consist of dexamethasone and bortezomib,comprising administering a therapeutically effective amount of ananti-CS1 antibody that binds the epitope cluster covered by amino acids170 to 227 of SEQ ID NO:1 to the subject.
 88. The method of claim 87,wherein the anti-CS1 antibody is a humanized IgG₁ antibody comprisingthe heavy chain variable region of SEQ ID NO:5 and the light chainvariable region of SEQ ID NO:6.
 89. The method of claim 88, in which theanti-CS1 antibody is administered intravenously at a dose fromapproximately 0.5 mg/kg to approximately 20 mg/kg.
 90. The method ofclaim 88, in which the anti-CS1 antibody is administered intravenouslyat a dose of approximately 10 mg/kg.
 91. The method of claim 88, whereinthe bortezomib is administered twice weekly over a 21 day cycle followedby a 10 day rest period.
 92. The method of claim 88, wherein theanti-CS1 antibody is administered as an intravenous infusion at a dosefrom 2.5 mg/kg to 20 mg/kg and wherein the bortezomib is administered asan intravenous infusion at a dose from 0.2 mg/m² to 2.0 mg/m².
 93. Themethod of claim 92, wherein the bortezomib is administered at anintravenous dose from 1.0 mg/m² to 1.3 mg/m².
 94. The method of claim93, wherein the bortezomib is administered at an intravenous dose of 1.0mg/m².
 95. The method of claim 93, wherein the bortezomib isadministered at an intravenous dose of 1.3 mg/m².
 96. The method ofclaim 92, wherein the anti-CS1 antibody is administered at anintravenous dose of 2.5 mg/kg.
 97. The method of claim 92, wherein theanti-CS1 antibody is administered at an intravenous dose of 5 mg/kg. 98.The method of claim 92, wherein the anti-CS1 antibody is administered atan intravenous dose of 10 mg/kg.
 99. The method of claim 92, wherein thepatient receives the anti-CS1 antibody once every 10 days.
 100. Themethod of claim 99, wherein the patient receives the bortezomib fourtimes in a three week cycle.
 101. The method of claim 100, wherein thebortezomib is given on days 1, 4, 8, and 11 followed by a 10 day restperiod.